The most likely situation is that you've filled your disk up, or run out of quota. It can't open the log file because it can't write to the directory, probably because it is full.
The "E72: Close error on swap file" is an error message from vim (do a google search), again caused by the fact that the swap file that vim uses (a dot file in the same directory as the file) can't be created. It's nothing to do with /proc/swap. Not sure what -1 means, but that's totally irrelevant - it's nothing to do with the OS Swap.